湿静力平衡温度及其在大气对流运动中的应用

The wet static-equilibrium temperature and its application to the convective movement of wet air

  • 摘要: 提出了一个新的大气动力-热力学温湿参量——湿静力平衡温度(Ts)。它与密度温度(Tρ)有密切关系。作为Ts的应用示例,简化了积云一维时变模式垂直运动方程;提出了“载水气块”和“非载水气块”统一的新的“对流有效位能”表达式。结合实例,计算了“载水气块”和“非载水气块”两种情况下的对流有效位能(分别记作CAPEw和CAPE)以及对流抑制能量(分别记作CINw和CIN)等,“载水气块”与“非载水气块”两种情况的“对流有效位能”及“对流抑制能量”有较大差异。作为强对流天气分析预报的重要参数,目前计算对流有效位能和对流抑制能量的通用公式存在一定缺陷;在对“对流有效位能”的理解方面存在某些模糊认识和盲点。从新的观察角度对“对流有效位能”的概念做了详细分析并进一步阐明了其确切含义。新的方案同样可以方便地在T-lnp图上进行稳定度分析,并可根据新的公式对T-lnp的某些缺点进行修正。

     

    Abstract: An new parameter of moisture-temperature have been proposed in regard to dynamics and thermodynamics of atmosphere, and this is the wet static equilibrium or the static equilibrium temperature of a saturated air (Ts). It has close relationship with density temperature (Tρ), but it is more suitable for application compared with density temperature in terms of the wet air convection. It could be used to simplify the vertical motion equation of the cumulus one-dimensional time varying mode. Serve as the application example of Ts, A new uniform calculational expression of the convective available potential energy (CAPE) is derived, based on the example of the air parcel with water during its reversible saturation adiabatic ascending process and the air parcel without water during its pseudo-adiabatic ascending process. We have calculated the convective available potential energy (respectively written as the CAPEW and CAPE), convection inhibition energy, level of free convection, equilibrium level (respectively written as CINw and CIN, LFCw and LFC, ELw and EL). By the contrast analysis, it is found that they are very different from each other. Now the general universal formulas to calculate the convective available potential energy and the convection inhibition energy shows many defects, and it needs to have an improvement. The new uniform calculation expression suggested in this paper can be used for analysis of degree of stability and further understanding the concept itself.

     

/

返回文章
返回